Study Of Spectral CT Multi-parameter Imaging In Predicting Lymph Node Metastasis And Perineural /lymphovascular Invasion Of Colon Cancer

Objective:To explore the application value of spectral CT multi-parameter imaging in predicting lymph node metastasis and perineural invasion（PNI）/lymphovascular invasion（LVI）of colon cancer before operation.Methods:The clinical and imaging datas of 64 colon cancer patients confirmed by pathology in the First Affiliated Hospital of Kunming Medical University from September 2021 to September 2022 were retrospectively collected,which including31 males and 33 females,aged from 31 to 90（61.7±12.9）years.According to the status of lymph node metastasis in postoperative pathology,these patients were divided into lymph node metastasis group（35 cases）and non-lymph node metastasis group（29 cases）.According to the presence of PNI/LVI,they were divided into the PNI/LVI positive group（29 cases）and the PNI/LVI negative group（35 cases）.The CT values of primary tumor on virtual mono-energetic images of 40ke V(CT_{40ke V})and90ke V(CT_{90ke V})in arterial and venous phase of spectral CT were measured on Philips Intelli Space Portal workstation.The iodine concentration（IC）and effective atomic number(Z_eff)of tumor and abdominal aorta or iliac artery at the same level also be measured,then the spectral curve slopeλ,normalized iodine concentration（NIC）and normalized effective atomic number(NZ_eff)were calculated.The differences of each spectral parameter between the two groups were compared and the receiver operating characteristic（ROC）curves were drawn for the quantitative parameters with statistically significant difference.The area under the curve（AUC）were calculated to evaluate the diagnostic efficacy of each parameter,and the optimal threshold,sensitivity and specificity of each parameter were determined according to the Youden index.Binary logistic regression model was used to analyze the diagnostic efficacy of combined parameters in predicting lymph node metastasis and PNI/LVI status of colon cancer.Results:1.64 patients with colon cancer were included in the study,including 35 in the lymph node metastasis group and 29 in the non-lymph node metastasis group.Compared to non-lymph node metastasis group,lymph node metastasis group had higher proportion of increased carcinoembryonic antigen（CEA）,higher CT_{40ke V},IC,NIC,Z_eff,λin arterial phase and higher CT_{40ke V},IC,NIC,Z_eff,NZ_eff,λin venous phase[the representative parameters were:the proportion of increased CEA:54.29%（19/35）vs 24.14%（7/29）;theλin arterial phase:2.14±0.61 vs 1.74±0.42;the IC in arterial phase:1.51±0.43 vs 1.21±0.30（mg/ml）;the Z_effin arterial phase:8.14±0.20 vs 7.99±0.16],the difference was statistically significant（all P<0.05）.However,there was no significant difference of CT_{90ke V},NZ_effin arterial phase and CT_{90ke V}in venous phase between the two groups（all P>0.05）.ROC curve showed that the diagnostic efficacy of each parameter in the arterial phase for predicting lymph node metastasis of colon cancer was higher than that in the venous phase.The predictive efficacy of the combined parameters in both phases were better than that of the individual parameter,and the combined parameters in the arterial phase had the highest predictive value,with an AUC of 0.801,sensitivity and specificity of 68.57%and 89.66%,respectively.2.Among the 64 colon cancer patients included in the study,29 were in the PNI/LVI positive group and 35 were in the PNI/LVI negative group.The spectral CT quantitative parameters CT_{40ke V},IC,NIC,Z_eff,NZ_effandλin the arterial phase and venous phase of the PNI/LVI positive group were higher than those in the negative group[the representative parameters were:theλin arterial phase:2.24±0.57 vs 1.73±0.43;the IC in arterial phase:1.58±0.40 vs 1.20±0.30（mg/ml）;the Z_effin arterial phase:8.17±0.20 vs 7.99±0.15],the difference was statistically significant（all P<0.05）.However,there was no significant difference of CT_{90ke V}in arterial phase and venous phase between the two groups（all P>0.05）.ROC curve showed that the diagnostic efficacy of each parameter in the arterial phase for predicting PNI/LVI of colon cancer was higher than that in the venous phase.The predictive efficacy of the combined parameters in both phases were better than that of the individual parameter,and the combined parameters in the arterial phase had the highest predictive value,with an AUC of 0.849,sensitivity and specificity of 89.66%and 74.29%,respectively.Conclusions:1.The quantitative parameters of CT_{40ke V},IC,NIC,Z_eff,NZ_eff,λon spectral CT and CEA are helpful to predict lymph node metastasis of colon cancer before operation,and the multi-parameter combined model has higher diagnostic value.2.The quantitative parameters of CT_{40ke V},IC,NIC,Z_eff,NZ_effandλon spectral CT have certain value in predicting preoperative PNI/LVI status of colon cancer,and the predictive efficacy of combined parameters are better than the individual parameter.